Help with identifying part sizes on a Bianchi Avenue

I am planning on changing the gears on my Bianchi Avenue, and I was wondering if anyone happened to know what sizes/threading certain parts use, or could tell me how to measure/look at the parts and find out myself.

I am wondering what kind of rear hub it has, and whether it takes a freewheel or cassette. I am also wondering what kind of chainrings it has (BCD, etc) and if they can be changed. And I'm not sure how to take the crank arms off either, which would be necessary to replace the chainrings. I want to change the chainrings from 42/32/22 to 52/42/32, or a 52/42 double if the smallest gear is on a spider and I can't find a replacement for it.

I was originally planning to buy a cheap road frame and build it up, but I noticed that my bike has geometry that is very similar to a Specialized Allez (and I looked up the dimensions, and my bike is very, very close to the 56cm Allez. Most of the tube lengths are the same. The top tube is exactly the same). I like the shape of my bike and I really like how it fits now, so I just want to put better gearing on it, and maybe butterfly or drop bars and call it a day. Probably skinnier tires as well, but not so small as to replace the rims.